1. Life Cycles of Stars

2. Life Cycles of Stars
THE MAIN FACTOR THAT DETERMINES THE LIFE CYCLE (PATH A STAR WILL TAKE) IS THE STAR’S MASS

3. Stage 1: for all stars no matter what their mass
Protostars

4. Protostars
All stars form in nebulas huge clouds of gas (hydrogen) in which stars are made.
Nebula are 1000’s of times bigger than our solar system
As part of the nebula the clouds collapses stars are “born: in them

5. Pillars of Creation

6. Stage 2: for all stars no matter what their mass
Main Sequence Phase

7. Main Sequence Star
Main Sequence is the longest phase of all stars life
How long a star remains in Main Sequence depends on its MASS.
Our sun is about half way through it’s main sequence of about 10 billion years

8. Nuclear fusion –changes one element into another (one kind of atom into another) this gives off energy in the form of HEAT and LIGHT
A protostar will not enter main sequence if it does not have enough mass and will become a brown dwarf
A proto star must have enough mass, and pressure to begin main sequence and be called a Star
Main Sequence & Nuclear Fusion

11. Stage 3: for all stars no matter what their mass
Red Giant Phase or for those very large stars Super Massive Red Giants

12. Red Giant
As the star changes all of it’s hydrogen into helium the outer layers of the star will become cooler
The layers will expand.
For our Solar System Mercury and Venus will most likely be engulfed with Earth very close to the sun so all living things will be gone.

15. Stage 4: For Low/medium Mass stars like the Sun
Planetary Nebula

16. The end of step 3 – Planetary Nebula

17. Planetary Nebula Starts the “Death” of a star like our Sun
Outer layers are expelled by solar winds
Returning materials to interstellar space

18. Stage 5: Low/medium mass Stars like Sun
White Dwarf –

19. White Dwarf Gravity will cause the red giant to collapse
The star is now much cooler and it collapses into a small white star
It still has the same original mass

24. Stage 6: for low mass stars like the Sun
Black Dwarf

25. Black Dwarf The star cools more and more
Eventually it will become a black mass emitting no light
It will then spend the rest of eternity drifting silently through space

28. Stars at least 6 X’s bigger than our sun!
At least six solar masses bigger than our Sun

29. Stage 3:for Giant/massive and super giant/super massive stars
Red Supergiant

30. Super Red Giant
This is the same as with the low mass stars however more elements are changed in the stars core hydrogen to helium, helium to carbon, carbon to iron

32. Stage 4:Giant/massive and Super giant/super massive stars
Super Nova

33. Supernova! The largest and most powerful explosions in the universe.
The red super giants literally blow themselves apart!

35. Supernova
All the atoms we are made from came originally from these giant supernova explosions.

37. Stage 5: for giant/massive stars
Neutron star

38. Neutron Star Giant stars at least 6 solar masses (
They are compact objects that are created in the cores of massive star during supernova The core of the star collapses, and crushes and leaves only the neutrons

39. Stage 5: for Super giant/super massive star
Black hole

42. Black hole After the supernova a huge mass is left behind.
Formed by stars that are 8 X’s or larger stellar masses than the Sun
Black holes can suck in nearby stars and solar systems.

43. Hertzsprung-Russell Diagram compares properties of stars

44. Observe the life stages of stars from birth to death